P0420, converter removal, magnaflow replacement write-up
05-15-2016, 01:31 PM
#1
Registered User
Thread Starter
P0420, converter removal, magnaflow replacement write-up
Since I couldn't find a detailed write-up, here's my take. What I had to google, hopefully can be found on YT!
OK. First the story:
Had the P0420, somewhat common DTC. I first had this come on after a troubling uphill climb on 1st gear at a red light a few years ago. Should've used 4-lo at the time. On a manual, can be scary on busy local streets.
I think I'm the 2nd/3rd owner. So naturally, the a/f and oxygen sensors come to mind for potential solutions to the code. Did that and after the codes were reset, did not come back...until a yr and half passed.
New DENSOs so I thought, exhaust leak. Sprayed everywhere with soapy water...manifolds, flange pipes, ah. The one between the front and rear converter had a small leak. Corrosion like any east coast 4runner.
Still didn't remove the P0420. And being located in a place that requires emissions testing sucks 'Sweaddy balls.'
With everything else in tip-top shape (sensors, fuel, plugs, wires, no intake/exhaust leaks), last culprit is cat converter. Converter is likely original. When the code re-appeared, odometer around 184,000 mi. I have Cali-type...so it was both front and rear. Twice the pain. Decided on Magnaflow. 5 yr warranty on most vendors, so yes, better deal than OEM. Anyway. Removal sucks.
Tools I had and needed:
-14mm socket (deep and reg size), combo wrench, hex bit -- for nuts
-17mm socket (deep and reg size) -- for the install of replacement bolts
-torque wrench
-3/8 extension (greater than 6")
-1/2 breaker bar with 3/8 adapter
-3/8 ratchet
-cheater pipe
-12mm ratcheting combo wrench (for a/f and oxy sensor nuts)
-MAPP torch with extension hose (I chose the self-starting type, more fun); this I bought specifically for this job
-mallet and chisel
-appropriate eyewear, face mask, gloves
Tools I needed but didn't have:
-Dremel two-speed rotary tool, corded (had the cutting wheels)
-Candle wax
Basically I spent the majority of the initial steps dremel cutting the 2 rusted bolt/nuts that held the rear converter to the muffler and all 8 heat shield fasteners for front and rear converters. I left the flange bolts between the front and rear untouched and gambled on the possibility of taking out the entire assembly. It's doable...but I needed to cut the converter hanger welds (later) and take off the heat shields. My idea was to cut them flush with the flange surface to as close as possible to make them pop loose with mallet and chisel. The drillout method did not work for me. Had too big of a drill and precision is difficult underneath and constant pressure was very exhausting (great pun). Well I took forever, so I tried my efforts at the top - the upper exhaust nuts where they attach to the crossover pipe.
This is where things got smoother. I wasn't using the torch properly at first with the flange bolts earlier, focusing flame directly on the bolt, which would soften the metal and make hammer out methods complicated as the old bolts would mushroom inside the flange. So with the upper exhaust studs, flame was focused around them, in back to back applications. Candle wax was then applied directly to the studs and surrounding flange surfaces. This method learned off a youtube video. Put PB out of my playbook honestly. All 3 nuts came off afterwards with the tools above. An alternate method I used on one nut was using the box end of the 14mm on the nut, and placing the 14mm hex bit through the open end. That same hex bit would then attach to the 1/2 breaker bar. The room for all that? Accessing through the passenger-side wheel well of course. Wish the oil filter was that easy.
Back to the flange bolts. Nearly dremel'd both sides and both ends. I dremel'd the bottom flanges where gaps were easily seen and worked my way to the sides. This allowed me to get the chisel in between and with gradual leverage, and subsequent heating/wax, I was able to hammer out the bonds that held the bolt leftover inside the exhaust flanges. With that and the heat shield fasteners, I found that the more that was dremel'd off, the less force it took to hammer them out. I'd gone through a few cutting wheels and nearly one reinforced one.
Finally. Removed the 12mm a/f and oxygen sensor nuts and removed the still like new sensors and their gaskets and secured them out of the way. I happened to have a pitman tie rod puller (doing lower ball joints next), so I used that to get the 2 rubber hangers off the converter. Mallet and punch would accomplish this as well. Was able to re-use them. At this point, the converter hangers can get cut off. Actually I bashed them off with the mallet.
Getting the old converter off after all that was relatively not too bad. Had to budge them past the muffler and was able to remove completely.
Install was a breeze in comparison. For the replacement bolts/nuts on the flanges (4 total), I used M10x1.25(thread pitch)x40mm bolts from Home Depot. The nuts would be the same thread pitch, but not sure on the M8. The nuts I happened to use were leftover flange nuts I had. Fit well on the magnaflow 447192 and 447225, which came with their own gaskets. I had to call the company to verify that only one gasket is used in between them both. For some reason I came with two.
Torque specs for the exhaust flange new bolts/nuts found online were only approximate to what I could best guess -- listed 35 ft/lbs. But with a sizeable gap still present, I wanted to be a bit more tighter so I went with 40 ft/lbs. The upper exhaust nuts were also my guess...same. A/f and oxygen sensor nuts are 14 ft/lbs, but by this time, I just went with feel. I'm ready to put this sucker off and drive.
Good enough to pass Cali emissions. And having a good scan tool is a good investment. Seeing the cat test indicator go solid after driving around without that crap P0420 is a huge sigh of relief. Had to reset the codes to restart the testing cycle.
If anything above needs to be corrected, please do. Hopefully this helps anyone!
I don't have a sawzall, cutting torch, or welder. I got the MAPP torch and dremel basically as new tools, including a corded drill, the latter that didn't work. I bought enough tools for now. So yes, what I put up is ONE method. Definitely don't need a shop or dumbass critic.
OK. First the story:
Had the P0420, somewhat common DTC. I first had this come on after a troubling uphill climb on 1st gear at a red light a few years ago. Should've used 4-lo at the time. On a manual, can be scary on busy local streets.
I think I'm the 2nd/3rd owner. So naturally, the a/f and oxygen sensors come to mind for potential solutions to the code. Did that and after the codes were reset, did not come back...until a yr and half passed.
New DENSOs so I thought, exhaust leak. Sprayed everywhere with soapy water...manifolds, flange pipes, ah. The one between the front and rear converter had a small leak. Corrosion like any east coast 4runner.
Still didn't remove the P0420. And being located in a place that requires emissions testing sucks 'Sweaddy balls.'
With everything else in tip-top shape (sensors, fuel, plugs, wires, no intake/exhaust leaks), last culprit is cat converter. Converter is likely original. When the code re-appeared, odometer around 184,000 mi. I have Cali-type...so it was both front and rear. Twice the pain. Decided on Magnaflow. 5 yr warranty on most vendors, so yes, better deal than OEM. Anyway. Removal sucks.
Tools I had and needed:
-14mm socket (deep and reg size), combo wrench, hex bit -- for nuts
-17mm socket (deep and reg size) -- for the install of replacement bolts
-torque wrench
-3/8 extension (greater than 6")
-1/2 breaker bar with 3/8 adapter
-3/8 ratchet
-cheater pipe
-12mm ratcheting combo wrench (for a/f and oxy sensor nuts)
-MAPP torch with extension hose (I chose the self-starting type, more fun); this I bought specifically for this job
-mallet and chisel
-appropriate eyewear, face mask, gloves
Tools I needed but didn't have:
-Dremel two-speed rotary tool, corded (had the cutting wheels)
-Candle wax
Basically I spent the majority of the initial steps dremel cutting the 2 rusted bolt/nuts that held the rear converter to the muffler and all 8 heat shield fasteners for front and rear converters. I left the flange bolts between the front and rear untouched and gambled on the possibility of taking out the entire assembly. It's doable...but I needed to cut the converter hanger welds (later) and take off the heat shields. My idea was to cut them flush with the flange surface to as close as possible to make them pop loose with mallet and chisel. The drillout method did not work for me. Had too big of a drill and precision is difficult underneath and constant pressure was very exhausting (great pun). Well I took forever, so I tried my efforts at the top - the upper exhaust nuts where they attach to the crossover pipe.
This is where things got smoother. I wasn't using the torch properly at first with the flange bolts earlier, focusing flame directly on the bolt, which would soften the metal and make hammer out methods complicated as the old bolts would mushroom inside the flange. So with the upper exhaust studs, flame was focused around them, in back to back applications. Candle wax was then applied directly to the studs and surrounding flange surfaces. This method learned off a youtube video. Put PB out of my playbook honestly. All 3 nuts came off afterwards with the tools above. An alternate method I used on one nut was using the box end of the 14mm on the nut, and placing the 14mm hex bit through the open end. That same hex bit would then attach to the 1/2 breaker bar. The room for all that? Accessing through the passenger-side wheel well of course. Wish the oil filter was that easy.
Back to the flange bolts. Nearly dremel'd both sides and both ends. I dremel'd the bottom flanges where gaps were easily seen and worked my way to the sides. This allowed me to get the chisel in between and with gradual leverage, and subsequent heating/wax, I was able to hammer out the bonds that held the bolt leftover inside the exhaust flanges. With that and the heat shield fasteners, I found that the more that was dremel'd off, the less force it took to hammer them out. I'd gone through a few cutting wheels and nearly one reinforced one.
Finally. Removed the 12mm a/f and oxygen sensor nuts and removed the still like new sensors and their gaskets and secured them out of the way. I happened to have a pitman tie rod puller (doing lower ball joints next), so I used that to get the 2 rubber hangers off the converter. Mallet and punch would accomplish this as well. Was able to re-use them. At this point, the converter hangers can get cut off. Actually I bashed them off with the mallet.
Getting the old converter off after all that was relatively not too bad. Had to budge them past the muffler and was able to remove completely.
Install was a breeze in comparison. For the replacement bolts/nuts on the flanges (4 total), I used M10x1.25(thread pitch)x40mm bolts from Home Depot. The nuts would be the same thread pitch, but not sure on the M8. The nuts I happened to use were leftover flange nuts I had. Fit well on the magnaflow 447192 and 447225, which came with their own gaskets. I had to call the company to verify that only one gasket is used in between them both. For some reason I came with two.
Torque specs for the exhaust flange new bolts/nuts found online were only approximate to what I could best guess -- listed 35 ft/lbs. But with a sizeable gap still present, I wanted to be a bit more tighter so I went with 40 ft/lbs. The upper exhaust nuts were also my guess...same. A/f and oxygen sensor nuts are 14 ft/lbs, but by this time, I just went with feel. I'm ready to put this sucker off and drive.
Good enough to pass Cali emissions. And having a good scan tool is a good investment. Seeing the cat test indicator go solid after driving around without that crap P0420 is a huge sigh of relief. Had to reset the codes to restart the testing cycle.
If anything above needs to be corrected, please do. Hopefully this helps anyone!
I don't have a sawzall, cutting torch, or welder. I got the MAPP torch and dremel basically as new tools, including a corded drill, the latter that didn't work. I bought enough tools for now. So yes, what I put up is ONE method. Definitely don't need a shop or dumbass critic.
Last edited by 75w90mantraN; 06-03-2016 at 03:28 PM. Reason: clarity, additional pics
05-16-2016, 06:07 PM
#4
Registered User
Thread Starter
Don't think a cheap aftermarket will pass CA state emissions. Where would such a deal for CARB compliant ones be online? I looked but they wound up usually around a few hundred. Besides, I'm not looking forward to another code pop up next year or two with cheap types. They likely don't come with warranty either. You pay for what you get.
Thanks for your comment about taking it to a shop. This post is more for those that are looking to make their garage THE shop.
As always, compliments appreciated. If OTHER suggestions or questions about it, by all means.
I have the old converter still intact so for better visuals, I can take more pictures of this potentially intimidating project to give better step-by-step on taking those ridiculously corroded fasteners on the other flanges.
Thanks for your comment about taking it to a shop. This post is more for those that are looking to make their garage THE shop.
As always, compliments appreciated. If OTHER suggestions or questions about it, by all means.
I have the old converter still intact so for better visuals, I can take more pictures of this potentially intimidating project to give better step-by-step on taking those ridiculously corroded fasteners on the other flanges.
05-16-2016, 06:51 PM
#6
Registered User
Thread Starter
All good man. Write-ups are hard to come by and this site could use a number. Pictures too. It's difficult to take shots solo. But it's too cool to pass. Hope it helps somebody.
UPDATE: Just put up new shots of the rest of the flange bolts takedown. Obviously easier when it's off the vehicle, but nonetheless, dremel'n both ends of the bolt and then making them as flush as possible, allows for smacking them loose with the mallet because there's less to hold up the flanges. Heat can help soften them up. Then repeat on the other bolt and go back and forth until they just give up on you (and they will, if you don't give up on them first
UPDATE: Just put up new shots of the rest of the flange bolts takedown. Obviously easier when it's off the vehicle, but nonetheless, dremel'n both ends of the bolt and then making them as flush as possible, allows for smacking them loose with the mallet because there's less to hold up the flanges. Heat can help soften them up. Then repeat on the other bolt and go back and forth until they just give up on you (and they will, if you don't give up on them first
Last edited by 75w90mantraN; 05-20-2016 at 08:53 PM.
